"plæsum" meaning in Old English

{
  "head_templates": [
    {
      "args": {
        "1": "ang",
        "2": "noun form"
      },
      "expansion": "plæsum",
      "name": "head"
    }
  ],
  "lang": "Old English",
  "lang_code": "ang",
  "pos": "noun",
  "senses": [
    {
      "alt_of": [
        {
          "word": "plæċum"
        },
        {
          "word": "found once in the Rushworth Gospel gloss"
        }
      ],
      "categories": [
        {
          "kind": "other",
          "name": "Anglian Old English",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Northumbrian Old English",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Old English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "Alternative form of plæċum, found once in the Rushworth Gospel gloss"
      ],
      "id": "en-plæsum-ang-noun-iUFUvxo7",
      "links": [
        [
          "plæċum",
          "plæcum#Old_English"
        ]
      ],
      "tags": [
        "alt-of",
        "alternative"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/ˈplæ.sum/"
    }
  ],
  "word": "plæsum"
}

{
  "head_templates": [
    {
      "args": {
        "1": "ang",
        "2": "noun form"
      },
      "expansion": "plæsum",
      "name": "head"
    }
  ],
  "lang": "Old English",
  "lang_code": "ang",
  "pos": "noun",
  "senses": [
    {
      "alt_of": [
        {
          "word": "plæċum"
        },
        {
          "word": "found once in the Rushworth Gospel gloss"
        }
      ],
      "categories": [
        "Anglian Old English",
        "Northumbrian Old English",
        "Old English entries with incorrect language header",
        "Old English non-lemma forms",
        "Old English noun forms",
        "Old English terms with IPA pronunciation",
        "Pages with 1 entry",
        "Pages with entries"
      ],
      "glosses": [
        "Alternative form of plæċum, found once in the Rushworth Gospel gloss"
      ],
      "links": [
        [
          "plæċum",
          "plæcum#Old_English"
        ]
      ],
      "tags": [
        "alt-of",
        "alternative"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/ˈplæ.sum/"
    }
  ],
  "word": "plæsum"
}

{
  "called_from": "form_descriptions/1698",
  "msg": "unrecognized head form: Northumbrian",
  "path": [
    "plæsum"
  ],
  "section": "Old English",
  "subsection": "noun",
  "title": "plæsum",
  "trace": ""
}